SCOTLAND witnessed a profound clash of constitutional legitimacy last week between the Holyrood and UK parliaments, as Theresa May blocked a referendum on independence. Wars have been started for less – but this needn't end in conflict. Supporters of independence should keep the heid and avoid “wildcat” ballots, civil disobedience or dark threats. Appearances are deceptive.

In fact, as a result of last week, another referendum is almost certain, and Theresa May has made a Yes victory very much more likely. She did this by appearing to diminish the standing of the Scottish Parliament, and by taking a capricious and unreasonable line on the timing of indyref2, as if she and she alone had the right to name the day. The Scottish voters, and only the voters, will decide this in the end, and while they may not be in referendum mood right now, they are watching events critically.

Opinions are hardening as Brexit does. Significantly, the Herald and the Scotsman, which both supported the Union in 2014, condemned Theresa May's rejectionism, insisting that the PM cannot supplant the Scottish Parliament as the source of democratic authority in Scotland. The Scotsman opined that her position was “reckless” and “deluded”; the Herald that it was “untenable”. Meanwhile, Tory-supporting London-based papers lapsed into hysterical denunciation of the First Minister, crying “betrayal” and “treachery”, and worse.

Theresa May's back was against the wall after the First Minister launched her pre-emptive strike on Monday. The UK Government feared that referendum talk that might unbalance the complex negotiations with Brussels over Brexit. May couldn't afford to fight a war on two fronts. And even supporters of independence had to concede that she had a reasonable case for saying that right now was not the time for a referendum.

But of course Nicola Sturgeon was not calling for a referendum “now”, but in around two year’s time to coincide with Britain’s departure from the European Union in March 2019, under the terms of Article 50 of the 2009 Lisbon Treaty. Moreover, Sturgeon’s timing is obviously negotiable, and could slip further back.

Was this a reasonable timetable? Conservatives and the UK Press insisted it was not; that it was a “mischievous” attempt to undermine the Brexit negotiations. But Theresa May did not give any real arguments to support this, only repeated assertions, in her interview on Thursday with ITV's Robert Peston, that “now is not the time”. To which the obvious follow-up question is: if not now, when?

She said that “the country had to come together” and that Scottish voters could not be expected to “vote blind” before the terms of Brexit were clear, but gave no indication about when that might be. Under Article 50, the terms of Brexit must be agreed with Brussels by the autumn of 2018, so that they can be ratified by the 27 EU nations before Brexit day. Trade talks might continue thereafter.

Clearly, there are many voters in Scotland who agree with May at least on her main point. They want to see what Brexit means too. But her equivocation suggested that she has no confidence in her own timetable, and that the Brexit process will not go as planned. This interpretation was amply reinforced by the Brexit Secretary David Davis’s shambolic and bad-tempered encounter with the Brexit Select Committee on Wednesday.

What happens now? Well, rightly, the First Minister is continuing with due parliamentary process, as laid down by the precedent of the 2014 referendum and the Edinburgh Agreement of 2012. She will put the matter to a vote of the Scottish Parliament this week. Assuming the Greens support the Scottish Government, Sturgeon will then formally request that the UK Government agrees to an order under Section 30 of the 1998 Scotland Act, authorising Holyrood to hold a referendum.

Number Ten will presumably reject this and, as the Scottish Secretary, David Mundell, put it, “refuse to enter discussions or negotiations on the matter”. It looks like an impasse: an unstoppable force colliding with an immovable object. But the odd thing about this constitutional war is that there is actually a large measure of agreement between the belligerents.

Theresa May has not ruled out a referendum indefinitely, though she has refused to discuss when it might take place. For her part, Nicola Sturgeon has agreed that Scottish voters need to see the terms of Brexit before they can make an informed choice about the future. A visitor from another planet, or perhaps Brussels, might see an obvious solution.

If this were the EU, civil servants would go off to draft a “framework” document or a “road map” outlining the principles under which a new referendum date should be decided. Principles such as: the terms of Britain’s exit from the European Union should be clear and all negotiations completed on Article 50; neither side should be able to delay the referendum for more than 18 months after that; Scotland would not seek to open discussions with Brussels before the referendum – that sort of thing. And if you think it through, jaw jaw might be better for May than war war.

The PM could legitimately argue that March 2019 on the dot is unreasonable, not least because Brussels negotiations invariably overshoot. The UK could insist that there is then a “cooling off|” period after Brexit happens – a breathing space before Scotland piles into a referendum campaign. It would be quite difficult for the Scottish Government to refuse this. It might also be difficult for Nicola Sturgeon to disagree with the principle that the referendum campaign should not interfere with the UK general election campaign in 2020. Or the Scottish elections in 2021. This could mean ScotRef not happening for five years.

Would Scotland wait that long? Some at the SNP Conference in Aberdeen have been muttering about an early Scottish election to force the matter, or an advisory or “wildcat” referendum organised by the Scottish Government without Westminster approval. Wha daurs meddle wi me! But the First Minister should set this aside. She would have to resign to force an early Holyrood election, and that could easily backfire. It would look like a de facto referendum, even UDI or a Unilateral Declaration of Independence. Most Scottish voters don't want a referendum right now, and they would like this even less. An unauthorised referendum would be boycotted by the unionists.

No, this can and should be a long game. After this hectic week, the Scottish Government can be pleased with their work. They've taken the initiative, forced Theresa May to recognise the inevitability of a referendum, and gate-crashed the Brexit process, making clear to Brussels that Scotland is a dissenting voice and serious about independence. The Scottish Tory leader, Ruth Davidson, was left defending the risible argument that because the SNP doesn’t have an overall majority in Holyrood it lacks a mandate. On that criterion, no Westminster government in modern history would have a mandate, since under a PR system an overall majority in Holyrood requires 50 per cent of the vote.

An unanswerable democratic mandate will be on the table later this week, if and when Holyrood votes for a referendum. The Tories have forgotten the cardinal rules of Scottish politics: that it is fatal to diminish the status of Holyrood; and that the surest way to increase support for independence is to tell Scots that they can't have it.